This invention relates to coated substrates and coated abrasive articles that contain energy-curable cyanate ester resins and a method of making the coated substrate and the abrasive articles.
Cyanate ester resins have been used in a variety of composite, adhesive, and coating applications, such as conductive adhesives, structural adhesives, protective coatings, structural composites, abrasive binders, and semiconductor encapsulants.
U.S. Pat. No. 5,766,277 describes a coated abrasive article with a backing, a make coat on the backing, and a plurality of abrasive particles. The make coat precursor is an energy-curable melt-processable resin containing an epoxy resin, a polyester component, a polyfunctional acrylate component, and a curing agent for crosslinking the epoxy resin. A method of producing coated abrasive articles is also described.
U.S. Pat. No. 6,077,601 also describes a coated abrasive article. This article includes a backing, a first binder on the backing, and a plurality of abrasive particles in the first binder. The first binder precursor is an energy-curable preferably, melt-processable resin containing an epoxy resin, an ethylene-vinyl acetate copolymer, and a curing agent for crosslinking the epoxy resin (which is cured to provide a crosslinked make coating). The binder precursors are preferably free of homopolymers and copolymers of olefinic monomers. The first binder precursor may also contain a polyfunctional acrylate component.
Briefly, the present invention provides an abrasive article comprising a plurality of abrasive particles incorporated into a bond system for a variety of grinding applications. The bond system comprises a make resin derived from a first curable precursor resin, which comprises a first energy-curable component comprising a cyanate ester resin and a first curing agent. This bond system additionally comprises a size resin derived from a second curable precursor resin, which comprises a second energy-curable component comprising a cyanate ester resin and a second curing agent.
In another aspect, the present invention provides a method of making an abrasive article comprising the steps of (1) providing a substrate; (2) applying to the substrate a make coat layer comprising an energy-curable make coat precursor resin comprising a cyanate ester resin and a first curing agent; (3) applying a multiplicity of abrasive particles to the make coat layer; (4) curing the make coat precursor resin; (5) applying over the abrasive particles a size coat layer comprising an energy-curable size coat precursor resin comprising a cyanate ester resin and a second curing agent; and (6) curing the size coat precursor resin.
In another aspect, the present invention provides a treated substrate comprising a backing material coated with a resin derived from a curable precursor resin. The curable precursor resin comprises an energy-curable component comprising a cyanate ester resin and a curing agent. This resin is useful, for example, for presize, saturant, subsize, and backsize treatments of substrates.
As used herein:
xe2x80x9ccyanate monomerxe2x80x9d or xe2x80x9ccyanate ester monomerxe2x80x9d are used interchangeably and mean a chemical substance (generally a monomer, oligomer, or pre-polymer) in which at least one xe2x80x94OCN group is bonded to an organic radical R through the oxygen atom, forming at least one Rxe2x80x94OCN bond; at least two xe2x80x94OCN groups are preferred because of commercial availability and their network forming property; and xe2x80x9cenergy curablexe2x80x9d means curing by means of any of electromagnetic radiation (ultraviolet and visible), electron beam, and thermal (infrared and heat) means or any combination thereof such as heat and light simultaneously, or in any sequence, e.g., heat followed by light, light followed by heat followed by light, and the like.
It is an advantage of the present invention to provide abrasive articles for high temperature grinding applications. These articles have unique properties suitable for severe grinding conditions and can perform as well as traditional phenolic resin-based abrasive articles. In addition, the optional polyfunctional acrylate component serves as a rheological modifier to the composition, which allows for better control of the penetration of the cloth treatment into the backing and orientation of abrasive grits in the make resin.
It is another advantage of the present invention to provide a method of making abrasive articles for high temperature grinding applications that involves rapid curing and processing, which reduces the curing cycle time as well as allows better positioning of abrasive particles on a substrate.
Other advantages of the invention include the absence of volatile organic compounds and consistent products resulting from smooth coating.
The details of one or more embodiments of the invention are set forth in the accompanying drawing and the description below. Other features, objects, and advantages of the invention will be apparent from the description and from the claims.